You can see the frequency shift, frequency distribution, and with the right equipment you can see the chemical composition. From this information you can determine the elemental composition of the early universe. This can be tested to see how the generations of stars evolved. This is important to us because the original universe was mostly hydrogen, a little helium, and tiny amounts of deuterium and lithium. Lithium and deuterium get burned up quick in stars so we don't see much of it in later generations. With the big stars we will see elements up to iron due to nucleosynthesis and eventually elements higher up when supernovas occur. In a very young galaxy (and perhaps this one isn't even young enough), not enough supernovas would have occurred to 'pollute' the stars and space around them. In any case, all of this information taken as a whole gives an independent verification of current theories on how old the universe is, what it was initially made up of, how the physics worked back then, and how all of this evolved over time to allow galaxies like ours that have many elements including ones produced in supernovas (like lead, gold, uranium, etc.).